The present invention relates to a fitting for the connecting of pipes, comprising a press-fit connection provided with a ring-shaped seat for sealing and/or holding elements and which can be sealingly connected to an inserted pipe end by means of cold forming, and a threaded connection, which can be connected to a pipe by means of a threaded connection, as well as a method for manufacturing a fitting.
A method for manufacturing a metallic press-fitting element is known from DE 100 29 479 in which a solid or hollow bar is produced as the starting material for the press-fitting element that is machined. This way of manufacturing a press fitting is relatively costly, in particular the machining method produces waste products.
A method for the manufacture of press fittings is known from DE 43 36 261 in which a blank is initially deflected in a die and then the blank is upset to form circular grooves at various places. The wall sections are then rolled dimensionally accurate with a roller. This method can indeed be used to produce press fittings for a press-fit connection. Other connections, however, cannot be produced with this method.
A press-fittable fitting is known from DE 39 19 496 in which several connecting pieces are provided on one cast or pressed body. These connecting pieces are formed as press sections, which are connectable to a pipe end by means of pressing, wherein the connecting pieces are cemented or welded to the body. The mating of the connecting pieces to the body to create a fitting is relatively costly, however.
It is thus the object of the present invention to create a fitting and a method for manufacturing a fitting which facilitate the effective production of a fitting with different connection types.
The fitting according to the invention comprises a press-fit connection, on which there is formed a ring-shaped seat for sealing and/or holding elements and which is connectable to an inserted pipe end by means of cold forming. It also comprises a threaded connection, which is connectable to a pipe by means of a threaded connection, wherein the fitting is produced in a single piece by means of forming. The need to combine different sections by means of joining, such as cementing or welding, is thus avoided. The different connection types formed by a threaded connection or a press-fit connection can be produced by means of a few steps of a method. Depending on the requirements, the walls are shaped and thickened by means of forming in order to obtain a corresponding fitting profile with only minimal use of material.
Preferably, a polygon is formed adjacent to the threaded connection, preferably in the shape of a hexagon. Thus the fitting can be fixed to the threaded connection during assembly by means of known tools. The thread can be created as internal thread or external thread.
The fitting is made preferably from a material with good cold forming properties, such as copper or steel. To ensure good ductility, copper with a fineness of over 99.8% can be used, such as CO-DHP.
According to the method according to the invention, a pipe section is pressurized and formed on one end to create a press-fit connection with a smooth-walled seat for inserting sealing and/or holding elements, and a middle section is formed to create a pipe-shaped polygon while thickening individual sections, wherein a thread is subsequently rolled down or cut into a second end of the pipe section to create a fitting with a press-fit connection and a threaded connection. In the section of the thread, the wall thickness can also be thickened previously by forming, depending on the material thickness of the starting material. Forming can thereby take place both at room temperature as well as in a heated state.
The hydroforming method is preferably used to form the pipe section, in which forming takes place under pressure with a fluid. This forming technique is gentle on the material and permits both contour changes as well as material thickening. Cold forging can also be used, depending on the geometry of the part.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.